World stocks kicked off a new quarter Wednesday with strong gains in Japan and losses in Europe after registering their best monthly performance since December 1999.

Wall Street looked set for losses, but MSCI's all-country world index was up slightly on the day, having risen 7.94 percent in March.

Its emerging market counterpart was up 1 percent. It gained 14.15 percent last month, the highest monthly rise since December 1993.

Investors were firmly focused on the meeting of G20 leaders in Britain due to begin later in the day, looking for more confirmation there will be coordinated efforts to ward off a prolonged slump in world economic growth.

The danger is that the outcome vastly disappoints the hype, Gary Dugan, chief investment officer of Merrill Lynch Global Wealth Management, said in a preview note.

There is the potential of a spat at the meeting over how much debt governments should take on in providing stimuli to their ailing economies.

U.S. President Barack Obama played down rifts between the world's leading economies and urged them to act together to find the fastest route out of global recession.

The mood in Europe, however, was downbeat. The pan-European FTSEurofirst 300 index of top shares was down 0.4 percent, although this was well off lows and followed a 3.5 percent rise in the previous session.

Earlier, expectations of a decision soon on struggling U.S. automakers lifted Japanese stocks, underlining the impact that government intervention in economics currently has on markets.

The New York Times said the White House was looking to ease U.S. auto maker General Motors into a controlled bankruptcy.

Japan's Nikkei, which contains major Japanese automakers, gained 3 percent.

STRONGER DOLLAR

The dollar was flat against major currencies having earlier been supported by the uncertainty over the fate of U.S. carmakers, which prompted investors to seek perceived safer assets and shun high yielders.

The euro was flat at $1.3252.

With (GM) bankruptcy as a viable option, the news has helped sour risk sentiment, said Lee Hardman, currency economist at Bank of Tokyo-Mitsubishi.

On euro zone government debt markets, the two-year Schatz yield was down 5 basis points at 1.235 percent. Ten-year yields was slightly lower at 2.983 percent.